There are multiple different types of radar. All of the radars
work off of the basic principle of the radar equation as found in the principles
section.

Doppler Radar: Dopplerizing an
existing radar adds the capability of measuring wind direction and speed by
measuring the Doppler effect. The radar measures what is called radial velocity.
This is the component of the wind going either toward or away from the radar.

There are currently two different types of radar that are being
experimented with. The first type that is in the final stages of development
is dual-polarized radar. The other that is being worked on is bistatic radar.

Bistatic
Radar: This is probably the newest instrument on the horizon for
radar since it was created in 1994. In the past, a problem occurred in detecting
the wind structure of a thunderstorm with a single Doppler radar. This was
a problem because if the winds were flowing perpendicular to the radar beam,
it could not resolve which direction they were flowing from. This problem
is corrected with bistatic radars. In a bistatic system, there is at least
one bistatic receiver and one single traditional monostatic weather radar.
In this system, the weather radar transmits a narrow beam and receives the
backscattered radiation. At the same time, one or more passive bistatic receivers
recover some of the other scattered radiation. Since this gives multiple angles
on the wind, many components of the wind can be measured simultaneously. This
creates the possibility of directly measuring 3-D winds with a single radar
system. There currently is only one bistatic radar network set up in the world.
That network is set up around the Montreal airport in Canada. The preliminary
results have been very promising, especially in areas like airports that require
a good understanding of wind flow. An example of the data is below. One can
see below in the data the direction and speed of the winds. This solves the
problem that single dopplers have. Single dopplers can only see wind direction
toward or away from the radar.